A relay, as a common electronic device, is configured to control the on/off of a circuit. A common relay includes a mechanical electronic relay, which generates an electromagnetic field by using an excitation coil to act on a relay armature, so as to control the on/off of a circuit by controlling the on/off of the armature. The biggest problem of the mechanical electronic relay is that it relies on the mechanical on and off of the armature, thus easily causing impacts, and having a limited life span.
Another common relay further includes a reed switch relay. By applying an electromagnetic field to a reed switch, the reed switch is turned off when the electromagnetic field is enabled, so that the circuit is switched on. When the magnetic field is less than the enabled magnetic field, the reed switch is turned off. The reed switch relay is also of a mechanical on/off type, and likewise easily causes impacts.
Similar to the reed switch, a magnetoresistive sensor can also be designed as a magnetoresistive switch, being advantageous in that the magnetoresistive switch does not have the problem of the mechanical on/off, and the on/off is controlled by using an electronic switch. Therefore, the theoretical service life can be infinite. As a result, if the magnetoresistive switch is made into a magnetoresistive relay by using an integrated electromagnetic coil, it can be used to replace the reed switch and will be superior to the reed switch relay in terms of performance. Moreover, the magnetoresistive switch further has the following problem that a common magnetoresistive switch outputs digital signals, including high-level signals and low-level signals. The magnetoresistive switch applicable to the relay needs to be designed to simulate on/off signals, can implement access to and control over an external circuit, and has a large-power function.